package com.localsocial.screenphone;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Stack;

import com.localsocial.oauth.RequestToken;
import com.localsocial.oauth.Verifier;
import com.localsocial.remote.exception.UnauthorizedException;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.widget.ImageView;
import android.content.res.Resources;

public class ImageLoader {
    
    private HashMap<String, Bitmap> cache = new HashMap<String, Bitmap>();    
    private File cacheDir;
    
    public ImageLoader(Context context){
        photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1);
        
        if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED)) {
            cacheDir = new File(android.os.Environment.getExternalStorageDirectory(),"ImageList");
        } else {
            cacheDir = context.getCacheDir();
        }
        if(!cacheDir.exists()) {
            cacheDir.mkdirs();
        }
    }
    
    final int stub_id = R.drawable.stub;
    public void DisplayImage(String url, Activity activity, ImageView imageView) {
        if(cache.containsKey(url)) {
            imageView.setImageBitmap(cache.get(url));
        } else {
            queuePhoto(url, activity, imageView);
            imageView.setImageResource(stub_id);
        }    
    }
        
    private void queuePhoto(String url, Activity activity, ImageView imageView) {
        photosQueue.Clean(imageView);
        PhotoToLoad p = new PhotoToLoad(url, imageView);
        synchronized(photosQueue.photosToLoad){
            photosQueue.photosToLoad.push(p);
            photosQueue.photosToLoad.notifyAll();
        }
        
        if(photoLoaderThread.getState() == Thread.State.NEW) {
            photoLoaderThread.start();
        }
    }
    
    private Bitmap getBitmap(String url) {
    	if (url.equals("noPicture")) {
        	return null;
        }
    	
        //identify images by hashcode
        String filename = String.valueOf(url.hashCode());
        File f = new File(cacheDir, filename);
        
        //from SD cache
        Bitmap b = decodeFile(f);
        if (b != null) {
            return b;
        }
               
        //from web
        try {
            Bitmap bitmap = null;
            InputStream is = new URL(url).openStream();
            OutputStream os = new FileOutputStream(f);
            Utils.CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        } catch (Exception ex){
        	ex.printStackTrace();
        	return null;
        }
    }
    
    /**
     * Decode images
     * @param f
     * @return bitmap of an image
     */
    private Bitmap decodeFile(File f){
        try {
            //decode image size
            BitmapFactory.Options o = new BitmapFactory.Options();
            o.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(new FileInputStream(f),null,o);
            
            //Find the correct scale value. It should be the power of 2.
            final int REQUIRED_SIZE = 50;
            int width_tmp = o.outWidth, height_tmp = o.outHeight;
            int scale = 1;
            while(true){
                if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE) {
                    break;
                }
                width_tmp /= 2;
                height_tmp /= 2;
                scale *= 2;
            }
            
            //decode with inSampleSize
            BitmapFactory.Options o2 = new BitmapFactory.Options();
            o2.inSampleSize = scale;
            return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
        } catch (FileNotFoundException e) {}
        return null;
    }
    
    /**
     * PhotoToLoad
     */
    private class PhotoToLoad {
        public String url;
        public ImageView imageView;
        public PhotoToLoad(String u, ImageView i) {
            url = u; 
            imageView = i;
        }
    }
    
    PhotosQueue photosQueue = new PhotosQueue();
    
    public void stopThread() {
        photoLoaderThread.interrupt();
    }
    
    /**
     * List of photos to download
     */
    class PhotosQueue {
        private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();
        
        //removes all instances of this ImageView
        public void Clean(ImageView image) {
            for(int j=0; j<photosToLoad.size();){
                if(photosToLoad.get(j).imageView==image) {
                    photosToLoad.remove(j);
                } else {
                    ++j;
                }
            }
        }
    }
    
    class PhotosLoader extends Thread {
        public void run() {
            try {
                while(true) {
                    //thread waits until there are any images to load in the queue
                    if(photosQueue.photosToLoad.size()==0) {
                        synchronized(photosQueue.photosToLoad){
                            photosQueue.photosToLoad.wait();
                        }
                    }
                    if(photosQueue.photosToLoad.size()!=0) {
                        PhotoToLoad photoToLoad;
                        synchronized(photosQueue.photosToLoad){
                            photoToLoad = photosQueue.photosToLoad.pop();
                        }
                        Bitmap bmp = getBitmap(photoToLoad.url);
                        cache.put(photoToLoad.url, bmp);
                        Object tag = photoToLoad.imageView.getTag();
                        if(tag!=null && ((String)tag).equals(photoToLoad.url)){
                            BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad.imageView);
                            Activity a = (Activity)photoToLoad.imageView.getContext();
                            a.runOnUiThread(bd);
                        }
                    }
                    if(Thread.interrupted())
                        break;
                }
            } catch (InterruptedException e) {
            }
        }
    }
    
    PhotosLoader photoLoaderThread = new PhotosLoader();
    
    /**
     * Used to display bitmap in the UI thread
     */
    class BitmapDisplayer implements Runnable {
        Bitmap bitmap;
        ImageView imageView;
        public BitmapDisplayer(Bitmap b, ImageView i) {
        	bitmap = b;
        	imageView = i;
        }
        public void run() {
            if(bitmap!=null) {
                imageView.setImageBitmap(bitmap);
            }
        }
    }
    
    /**
     * Clear cache
     */
    public void clearCache() {
        //clear memory cache
        cache.clear();
        
        //clear SD cache
        File[] files = cacheDir.listFiles();
        for(File f:files) {
            f.delete();
        }
    }
}